add Feature/debugger detection (#12)

* add DebuggerDetection

* add DebuggerDetection to example app

* simplify checks, remove unused code

- threatDetected() condition fixed and simplified.
- private isTracerPidSet() simplified as a single-expression function.
- private isPortInUse() simplified as a single-expression function.
- removed unnecessary string casting from val adbPorts list.
- removed val adbConsolePorts (not yet used).

Author: ha-ja

example/app/src/main/java/com/exxeta/mobilesecuritytoolkitexample/ThreatStatusList.kt

@@ -59,6 +59,11 @@ fun ThreatStatusList() {
             "Running the application in an Emulator",
             reportedThreats.contains(ThreatDetectionCenter.Threat.SIMULATOR),
         ),
+        ThreatStatus(
+            "Debugger",
+            "A tool that allows developers to inspect and modify the execution of a program in real-time, potentially exposing sensitive data or allowing unauthorized control",
+            reportedThreats.contains(ThreatDetectionCenter.Threat.DEBUGGER),
+        ),
         ThreatStatus(
             "Passcode",
             "Indicates if current device is unprotected with a passcode. Biometric protection requires a passcode to be set up",

securitytoolkit/src/main/java/com/exxeta/securitytoolkit/ThreatDetectionCenter.kt

@@ -2,6 +2,7 @@ package com.exxeta.securitytoolkit
 
 import android.content.Context
 import com.exxeta.securitytoolkit.internal.AppSignatureDetection
+import com.exxeta.securitytoolkit.internal.DebuggerDetection
 import com.exxeta.securitytoolkit.internal.DevicePasscodeDetection
 import com.exxeta.securitytoolkit.internal.EmulatorDetector
 import com.exxeta.securitytoolkit.internal.HardwareSecurityDetection
@@ -17,6 +18,7 @@ import kotlinx.coroutines.flow.flow
  * - [areHooksDetected]: to check for injection (hooking) tweaks
  * - [isSimulatorDetected]: to check if the app is running in a simulated
  * environment
+ * - [isDebuggerDetected]: to check if the app is being traced by a debugger
  * - [isDeviceWithoutPasscodeDetected]: to check if device is protected with a
  * passcode
  * - [isHardwareProtectionUnavailable]: to check if device can use
@@ -52,6 +54,9 @@ class ThreatDetectionCenter(private val context: Context) {
     val isSimulatorDetected: Boolean
         get() = EmulatorDetector.threatDetected()
 
+    val isDebuggerDetected: Boolean
+        get() = DebuggerDetection.threatDetected()
+
     /**
      * Performs check for Device Passcode presence
      * Returns `false`, when device is **unprotected**
@@ -102,6 +107,9 @@ class ThreatDetectionCenter(private val context: Context) {
             if (EmulatorDetector.threatDetected()) {
                 emit(Threat.SIMULATOR)
             }
+            if (DebuggerDetection.threatDetected()) {
+                emit(Threat.DEBUGGER)
+            }
             if (DevicePasscodeDetection.threatDetected(context)) {
                 emit(Threat.DEVICE_WITHOUT_PASSCODE)
             }
@@ -122,6 +130,7 @@ class ThreatDetectionCenter(private val context: Context) {
         ROOT_PRIVILEGES,
         HOOKS,
         SIMULATOR,
+        DEBUGGER,
         DEVICE_WITHOUT_PASSCODE,
         HARDWARE_PROTECTION_UNAVAILABLE,
     }

securitytoolkit/src/main/java/com/exxeta/securitytoolkit/internal/DebuggerDetection.kt

@@ -0,0 +1,50 @@
+package com.exxeta.securitytoolkit.internal
+
+import android.os.Debug
+import java.io.FileReader
+import java.net.InetSocketAddress
+import java.net.Socket
+
+
+/**
+ * A Detector object for debugger
+ */
+internal object DebuggerDetection {
+
+    private val adbPorts = (5555..5585 step 2)
+
+    /**
+     * Exposes public API to detect debugger
+     *
+     * @return
+     * - `true` if debugger is detected.
+     * - `false` if no debugger is detected.
+     */
+    fun threatDetected(): Boolean {
+        return Debug.isDebuggerConnected() || Debug.waitingForDebugger() || isAdbPortListening() || isTracerPidSet()
+    }
+
+    private fun isTracerPidSet(): Boolean = try {
+        FileReader("/proc/self/status").buffered().use { br ->
+            br.lines().anyMatch {
+                it.startsWith("TracerPid:") && it.split(":")[1].trim() != "0"
+            }
+        }
+    } catch (e: Throwable) {
+        false
+    }
+
+    private fun isAdbPortListening(): Boolean {
+        return adbPorts.any { isPortInUse(it) }
+    }
+
+    private fun isPortInUse(port: Int): Boolean = try {
+        Socket().use { socket ->
+            socket.connect(InetSocketAddress("127.0.0.1", port), 200)
+        }
+        true
+    } catch (e: Throwable) {
+        false
+    }
+
+}